This invention relates generally to washing machines for washing fabrics and items of clothing and more particularly, to a roller thrust bearing assembly for a washing machine brake.
Known clothes washing machines generally include a cabinet enclosing an outer water-retaining tub and a basket is located within the tub. A transmission is located adjacent the tub and the transmission produces both an agitating movement and a continuous direct spin depending on the rotation direction of the motor. Particularly, an input shaft extends to the transmission from a pulley which is coupled to the motor by a belt. The input shaft extends through an actuator cam and a brake assembly positioned between the transmission and the pulley. The actuator cam cooperates with a brake hub to actuate, i.e., release and engage, the brake.
The actuator cam is supported on an angular contact bearing assembly which includes a snap ring secured within a groove machined into an input tube. The input shaft extends through the input tube. A counter bore is machined into the actuator cam, and an angular contact bearing is positioned within the counter bore. The angular contact bearing is supported by the snap ring. A washer typically is located between the snap ring and the angular contact bearing.
Since the angular contact bearing assembly is not easily accessible, the assembly generally must be xe2x80x9cpermanentlyxe2x80x9d lubricated in that the assembly must be able to retain lubrication over its life without requiring replenishment. Further, the above described angular contact bearing assembly is expensive to fabricate. For example, machining a counter bore in the actuator cam and machining a slot in the input tube to receive the snap ring are time consuming and labor intensive fabrication processes.
In operation, when the machine is to operate in the spin cycle, rotation of the actuator cam causes the brake hub to lift away from the cam and the brake releases. Under these conditions, significant downward axial forces are generated. As a result, the angular contact bearing assembly is subjected to high stresses due to the significant downward axial forces and also is subjected to low amplitude vibrations generated during the spin cycle.
It would be desirable to reduce the stresses on the bearing assembly and enable the bearing assembly to receive unlimited lubrication over its life. It also would be desirable to provide such an angular contact bearing assembly which is less expensive to assemble than the angular contact bearing assembly described above.
These and other objects may be attained by a thrust bearing assembly located at an upper end of the input shaft just below an input pinion engaged to the upper end of the shaft. The thrust bearing assembly, in one embodiment, includes a cage and bearing assembly positioned between washers. The thrust bearing assembly is supported on a bronze flange bearing having a bore, and the input shaft extends through the bore. The flange bearing is supported by the transmission housing. The thrust bearing assembly is located within a lubrication reservoir formed by the transmission housing and the reservoir typically is filled with a lubricant.
In the above described configuration, the angular contact bearing assembly is eliminated. In addition, the counterbore in the actuator cam is eliminated. Therefore, the time consuming and labor intensive machining processes required with the known angle contact bearing assembly are eliminated, and the above described thrust bearing assembly is believed to be lower in cost than the known bearing assemblies.
In operation, the thrust bearing assembly absorbs the downward axial forces on the input shaft during the spin cycle. Specifically, when the machine operates in the spin cycle, the axial forces are transferred through the actuator cam, the pulley hub, and the shaft to the input pinion. The input pinion rides on the upper washer of the bearing assembly and, therefore, the downward forces on the input pinion are transferred to the thrust bearing.
The above described thrust bearing assembly is believed to have a high load capacity and easily handles the load generated during the spin cycle. Further, since the thrust bearing is located in the lubrication reservoir, the bearing should receive ample lubrication throughout its life and need not be a xe2x80x9cpermanentlyxe2x80x9d lubricated type bearing. In addition, the bearings of the cage and bearing assembly are randomly oriented at the end of each agitation cycle and therefore, are less prone to wear.